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UPSC Prelims 1987 · World Geography · Earth in Space
Which of the following planets has no moon?
- (a) Mars
- (b) Venus
- (c) Jupiter
- (d) Saturn
Show the answer and explanation
Answer: (b) Venus
Venus has no moon (nor does Mercury).
The idea
A natural satellite is a body that orbits a planet or another larger body. Having a moon is not part of the definition of a planet. The presence of rings is also a separate property and does not determine whether a particular planet has a moon.
Why the others are wrong
(a) Mars has two moons (Phobos, Deimos).
(c) Jupiter has dozens of moons.
(d) Saturn has the most moons.
Also know
Mercury also has no known natural moon. Earth has one, while Mars has Phobos and Deimos. The outer planets have many moons, including Jupiter’s Io, Europa, Ganymede and Callisto, and Saturn’s Titan. Their known moon totals change with new discoveries, so an undated numerical ranking is unsafe.
🔒 No moons: Mercury, Venus.
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